Zipper's Performance 317-105 User Manual

Overview, Avoiding heat related failures, Included and additional required parts

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Zipper's Performance Products, 6655-A Amberton Dr., Elkridge, MD 21075 Internal Ignition Part No. 317-105
Tel: (410)-579-2828 Fax: (410)-579-2835


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Installation Instructions for Internal
Ignition Part No. 317-105



Zipper's Internal Ignition Part No. 317-105 is

intended for use with Harley-Davidson



motorcycle engines. The Zipper's Internal Ignition
replaces the original equipment (OE) electronic ignition
system on 1978-99 models. The unit mounts in the
gear case cover and uses the standard H-D


rotor. It can also be used on earlier models with
breaker points and mechanical advance.

The Zipper's Internal Ignition offers adjustable

advance, adjustable RPM limit settings in 100 RPM
increments, and switch selectable single or dual fire
modes. Single fire mode improves starting, reduces the
occurrence of backfiring at low RPM, and improves
power at high RPM. A red status LED flashes when the
engine reaches top dead center (TDC) and allows easy
static timing. The status LED also provides diagnostic
information. A green VOES LED illuminates when the
VOES (vacuum switch) input is active.

A special feature allows use of the tachometer

wire for a PC link to a laptop computer when the
engine is not running. Individual units can be
programmed with a custom advance curve and other
engine parameters such as rear cylinder timing offset.
The use of the tachometer wire for the PC link
eliminates the need to remove the outer cover plate.

All 317-105 units log engine operating data that

may be downloaded and viewed with our Operating
Statistics software. Units manufactured starting
January, 2006 include a build-in temperature sensor
and logging of temperature data.


Heat kills electronics. The 317-105 uses

electronic devices rated for operation at 105 deg C
(221 deg F), the highest rating available. The unit can
tolerate somewhat higher temperatures, but exposure
to temperatures above 125 deg C (257 deg F) will
greatly reduce life expectancy. We sometimes see
problematic applications where several module failures
have occurred. The failure mode is a classic thermal
intermittent where the module stops firing one cylinder

when it gets hot. We have found that these problematic
applications share one or more of the following

• VOES switch removed or non-functional. All street

driven engines require vacuum advance. Without
vacuum advance at idle and part throttle,
thermodynamic efficiency is reduced and engine
temperatures increase significantly.

• Improper carburetor jetting resulting in lean air/fuel

ratio (AFR). A lean AFR will cause the engine to
run very hot. All performance engine modifications
necessitate carburetor rejetting. Carburetors are
never correctly jetted out-of-the-box. The only
practical means of correctly jetting a carburetor is
to test the motorcycle on a chassis dyno equipped
with an exhaust gas sniffer.

• Lack of an oil cooler on a 95 CID or larger engine.
• Exhaust pipe without heat shield in close proximity

to the nose cone.

If any of the above applies to your application,

the 317-105 may be exposed to excessive
temperatures resulting in reduced life expectancy. We
suggest that you use our Operating Statistics software
to monitor temperature levels. If excessive
temperatures are encountered and cannot be
remedied, you should consider using an external


All units include a parts bag with crimp terminals

for coil and VOES hookup and a Packard Weather
Pack connector set intended for installation on the
tachometer wire to provide an access point for the PC

FL series Big-Twin

models manufactured prior

to 1985, FX series Big-Twin

and XL Series Sportster

models manufactured prior to 1984, and all models
with original equipment breaker points will require H-D

timing rotor P/N 32402-83 or an equivalent aftermarket